1. Field of the Invention
The present invention relates to a method for manufacturing a golf club head with scorelines. More specifically, the present invention relates to method for manufacturing a golf club head with scorelines utilizing a tumbling process.
2. Description of the Related Art
The prior art discloses various methods to manufacture golf club heads, especially iron-type golf club heads. For example, Rogers, U.S. Pat. No. 4,027,885 for Golf Iron Manufacture, discloses scoring grooves into a face for the club head.
Taylor, U.S. Pat. No. 4,077,632 for a Lined Face For A Golf Club discloses grooves in compliance with the Rules of Golf at that time.
Moore, U.S. Pat. No. 4,558,505, for a Method of Making Weighted Metal Golf Club Head discloses at process for making an iron-type golf club head.
Shira, U.S. Pat. No. 4,768,787, for a Golf Club Including High Friction Striking Face discloses grit blasting the horizontal grooves to provide a friction generating surface when the striking surface of the golf club head engages a ball.
Stuff, U.S. Pat. No. 5,354,059, for Golf Club Heads With Means For Imparting Corrective Action, discloses a club head with at least two non-parallel sets of grooves.
Funk, U.S. Pat. No. 5,487,543, for a Shot Peened Golf Club Head, discloses shot peening the striking surface of a golf club head.
Mogan, U.S. Pat. No. 6,059,670, for a Golf Club Having A Head With A Hard Multilayer Striking Surface And Method For Making The Same, discloses manufacturing a club head by heat treatments, vacuum treatments, and roughening.
Doolen, U.S. Pat. No. 6,179,725, for a Golf Club Having Angular Grooves discloses grooves oriented at various angles.
Hirota, U.S. Pat. No. 6,193,615, for a Head Of Golf Clubs That Spins More, discloses a face having grooves that allow for pressure to act specially on the edges of the grooves to increase ball spin.
Vokey et al, U.S. Pat. No. 7,473,187, for Spin Milled Grooves For A Golf Club, discloses machining grooves into a face.
Hettinger et al., U.S. Pat. No. 7,452,283, for a Putterhead With Dual Milled Face Pattern, discloses milling grooves into a face of a putter.
Kennedy, III, U.S. Pat. No. 7,179,175, for a Golf Club Having Stepped Grooves, discloses a golf club head with V-shaped and U-shaped grooves.
Scoreline designs generally have a cross-section geometry that includes two edges, two side walls and a bottom. The side walls are at a predetermined angle from a vertical line. Usually, each wall has more than one section and those sections are straight or curved. Alternatively, the scoreline design is a “V” shape, in which case there is no bottom other than a vertex or fillet radius.
Iron-type golf clubs having scorelines with sharp edges and relatively vertical side walls are advantageous to golfers since such sharp edged grooves allow golfers to induce higher levels of spin on a ball struck with such an iron-type golf club having sharp edged grooves. Iron-type golf clubs without sharp edged grooves or essentially vertical side walls will induce less spin when impacting a golf ball, especially higher-lofted (40 degrees+) golf clubs.
Traditionally, grinding has been used for material removal of iron-type golf clubs, but process variation during grinding has resulted in scoreline edges that are too sharp or scoreline widths that are too inconsistent.
Previous methods also used several belting steps to grind and skin the club head before finishing.
Other methods of scoreline fabrication such as machining or forming are too expensive or impractical to be used with cast iron-type golf clubs.